Abstract
The present study was carried out to investigate the effect of fertilization levels, years of adding fertilizers, and age of growth rings on the percentages of the chemical components of young Pinus brutia Ten. Trees grown in Nineveh forest. Analysis of variance shows that all factors with their interactions have significantly affected all the chemical components except the factor of the years of adding fertilizer as there has no significant effect on the percentages of extracts and the interaction of the years of adding fertilizer and fertilizing levels as there has been no effect on the percentages of extracts in ethanol-benzene. Fertilizing treatments have generally shown not clear trend in the increase percentages of ethanol-benzene extracts, while a significant increase in holocellulose and ash percentages were noticed. The increase in the levels of fertilizing treatments has led to a decrease in the percentages of lignin and hot-water extracts compared with samples that have not received fertilizer. The fertilizing treatment (70 gm. Compound fertilizer, 750 ppm. Iron and 45 ppm. Zinc) compared with the non-fertilized trees have given the highest ratios of increase in the percentages of holocellulose as it has reached (11.21 %), and (72.22 %) for the ash, and the highest ratio of decrease in the percentage of lignin (26.36). It has been evident that providing fertilizer for two successive years (the fourth and fifth years of age) has led to a higher increase in the percentages of holocellulose and ash and a highest decrease in lignin compared to the addition for one year (fourth year). It is found that the fertilizing treatment (70 gm compound fertilizer, 750 ppm iron, and 30 ppm. Zinc) provided for two successive years have more effecting decreasing the percentage of lignin. The highest increase in the holocellulose obtained from the interaction effect of (70 gm compound fertilizer, 750 ppm. Iron, and 30 ppm. Zinc) provided for one year, while the same treatment provided for two successive years has led to an increase in ash content. According to the results obtained, we can state that the ratios of the studied components are still within the ranges that are industrially acceptable, so these woods although fertilized are useful to be used in the wood industries, especially in paper, fiberboards, and particleboards.
